Communication systems providing mobility for the users thereof are known. A well-known example of such mobile communication systems is the public land line mobile network (PLMN), of which cellular communications networks are an example. Another example is a mobile communication system that is based, at least partially, on use of communication satellites.
In such systems, the mobile network apparatus and/or user equipment such as a mobile station can be employed for provision of information regarding the geographical location of the user equipment and thus the user thereof. The position of mobile user equipment, and the equipment's user, can be positioned by various techniques. For example, fairly accurate geographical location information can be obtained based on the known satellite based GPS (Global Positioning System). More accurate location information can be obtained through differential GPS techniques.
Another possibility is to use a location service based on a cellular telecommunications system. In this approach, the cells or similar geographically limited radio access entities and associated controllers of the communication system are utilised in production of at least a rough estimate of the current location of the mobile user equipment. To improve the accuracy of the location information the communication system may be provided with specific location measurement units that provide more accurate data concerning the location of user equipment within the service area of the cellular system. It is also possible to ascertain a geographical location when the mobile user equipment is located within the coverage area of a visited or “foreign” network. The visited network may be made capable of transmitting the location of the mobile user equipment back to the home network, e.g. to support services that are based on location information or for the purposes of routing and charging. The production of data for the location determinations does not form an essential element of the present invention, and is thus not described in any greater detail herein.
The location data may be processed in a specific location service entity that is implemented either within the cellular system or connected thereto. The location data may also be processed in the user equipment that is provided with appropriate processing capacity. The location service entity provided by the communication system may serve different clients via an appropriate interface.
The location information may be used for various purposes, such as for location of a mobile telephone that has made an emergency call, for locating vehicles or given mobile subscribers and so on. In general, a client such as a User Equipment or another entity wishing to receive location information regarding a User Equipment may send a request for such information to the location service provision entity. The location service provisioning entity will then process the request, obtain the required data and generate an appropriate response.
An example of the provision of the location information by a PLMN is described in more detail 3rd Generation Partnership Project (3GPP) technical specifications, see e.g. 3GPP TS 23.271 version 4.2.0, titled “Functional stage 2 description of LCS”, June 2001.
According to the 3GPP specification a location service (LCS) server entity referred to as a Gateway Mobile Location Center (GMLC) is provided for managing the location services. The GMLC is for gathering and storing various data that may be used in provision of location information for location service clients (LCS clients). The LCS Client may make use of that location information for various services/applications. A possible application comprises a LCS client arranged to provide location information in response to a request for non-call related location information. Such a request for location information is referred to in the 3GPP specifications as a non-call related MT-LR (Mobile Terminated Location Request).
Use of a so-called “Authorized UE List” has been proposed. This list contains Mobile Subscriber ISDN (MSISDN) numbers or groups of MSISDNs that are authorised to initiate a location information provision procedure. That is, MSISDNs or groups of MSISDN are listed for which the LCS Client may issue a non-call related MT-LR. Separate lists of MSISDNs may be associated with each distinct external or non-call related client identity.
The LCS Client who is external to the PLMN system may only be enabled to validly issue location information requests for those MSISDNs that are found on the “Authorized UE List”. That is, the LCS client's request may only be responded for subscribers who subscribe to the location services provided by the PLMN, as their MSISDNs would not otherwise appear on the list.
Request from the LCS Client are authenticated based on a combination of a Client ID and password stored in a LCS Client profile at the LSC server (e.g. the GMLC) and authorized based on the “Authorized UE List”. That is, the LCS client is authorised to receive location information from the GMLC entity if the requesting user equipment (UE) is found from the list.
Whilst provision of location information from the operator's network (location middleware) to an LCS client or other third party can provide some advantages to the user, there is also the issue of privacy to be considered. For example, passing the MSISDN to the LCS client or other third party would enable both identification of the user and their location. Enabling access to such a combination of information represents a serious privacy invasion for many users. It is therefore desirable to provide a mechanism for controlling provision of such information.